This paper deals with methods for calculating frequency characteristics of high frequency four-terminal-pair coaxial impedance standards. An analytical calculation for coaxial resistance and capacitance standards was performed at frequencies up to 200 MHz. For verification of the used method, numerical calculations based on domain FEM (Finite element method) in low and high frequency ranges are presently under investigation. The paper describes and summarizes first results, which will serve as a base for ongoing work on evaluating the effects of constructional limitations of four-terminal-pair impedance standards.